Heat exchanger and manufacturing method for heat exchanger

Abstract

To provide a heat exchanger and a manufacturing method for the heat exchanger that can restrain a brazing material provided in connection parts to first pipes in plate laminated bodies from flowing into second refrigerant flow passages.SOLUTION: A manufacturing method for a heat exchanger includes: a brazing step of simultaneously brazing heat exchange parts (40A and 40B), plate laminated bodies (50 and 60), and first pipes (38, 39, 38a, 39a, 13b, and 12b), thereby fixing fins (41) and heat transfer pipes (42) to one another, fixing plates (521, 522, 523, 524, 525, 621, 622, 623, 624, and 625) adjacent in a lamination direction, to one another, and connecting the heat exchange parts (40A and 40B) and the first pipes (38, 39, 38a, 39a, 13b, and 12b) to the plate laminated bodies (50 and 60); and a step of directly or indirectly connecting valve joints (80a and 80b) or auxiliary pipes (13a and 12a) to the first pipes (38, 39, 38a, 39a, 13b, and 12b) after the brazing step.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to heat exchangers and methods for manufacturing heat exchangers. [Background technology]

[0002] Patent Document 1 discloses a heat exchanger. The heat exchanger described in Patent Document 1 has a heat exchanger body and a refrigerant distributor. The heat exchanger body has refrigerant flow paths. The refrigerant distributor distributes and supplies refrigerant to multiple predetermined flow path portions in the heat exchanger body. The refrigerant distributor has a plate-shaped distribution member and is composed of overlapping plate-shaped members including this plate-shaped distribution member. The plate-shaped distribution member consists of a center plate and an underplate. The center plate has a refrigerant branching flow path portion. The refrigerant branching flow path portion has a refrigerant throttling function to supply refrigerant at a predetermined flow rate to multiple predetermined flow path portions in the heat exchanger body. The underplate has refrigerant inlet holes and refrigerant outlet holes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-125652 Summary of the Invention [Problem to be solved by the invention]

[0004] When a brazing material such as a clad material is provided to connect piping to the inlet and outlet holes of the underplate, if the inlet and outlet holes are left hollow (with no piping connected to the inlet and outlet holes) when brazing multiple plate-shaped components, the brazing material may melt and flow into the refrigerant flow path in the refrigerant distributor, resulting in clogging of the flow path.

[0005] An object of the present disclosure is to make it possible to prevent the brazing material provided at the connection portion of the plate stack with the first pipe from flowing into the second refrigerant flow path. [Means for solving the problem]

[0006] The first aspect relates to a method for manufacturing a heat exchanger. The method for manufacturing the heat exchanger includes simultaneously brazing a heat exchange section (40A, 40B) including fins (41) and heat transfer tubes (42) having a first refrigerant flow path (42c) formed therein, a plate stack (50, 60) including a plurality of stacked plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) having a second refrigerant flow path (51, 61) formed therein and communicating with the first refrigerant flow path (42c), and a first pipe (38, 39, 38a, 39a, 13b, 12b) having a third refrigerant flow path (W1) formed therein and communicating with the second refrigerant flow path (51, 61), to thereby obtain a heat exchanger. The method includes a brazing step of fixing the fins (41) and the heat transfer tubes (42) to each other, fixing the plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) adjacent to each other in the stacking direction, and further connecting the heat exchange section (40A, 40B) and the first pipe (38, 39, 38a, 39a, 13b, 12b) to the plate stack (50, 60), and a step of directly or indirectly connecting a valve joint (80a, 80b) or an auxiliary pipe (13a, 12a) to the first pipe (38, 39, 38a, 39a, 13b, 12b) after the brazing step. In the brazing step, with the heat exchange units (40A, 40B) and the first pipes (38, 39, 38a, 39a, 13b, 12b) assembled to the plate stack (50, 60), the heat exchange units (40A, 40B), the plate stack (50, 60), and the first pipes (38, 39, 38a, 39a, 13b, 12b) are brazed together at the same time.

[0007] In the first aspect, the brazing material provided at the connection portion (V) of the plate stack (50, 60) with the first pipe (38, 39, 38a, 39a, 13b, 12b) can be prevented from flowing into the second refrigerant flow path (51, 61).

[0008] In a second aspect, in the method for manufacturing a heat exchanger of the first aspect, after the brazing step, the method includes a step of connecting second pipes (38b, 39b) between the first pipes (38a, 39a) and the valve joints (80a, 80b).

[0009] In the second embodiment, the valve joints (80a, 80b) can be indirectly connected to the first pipes (38a, 39a) through the second pipes (38b, 39b).

[0010] In a third aspect, in the second aspect, the second pipes (38b, 39b) and the valve joints (80a, 80b) are made of the same material.

[0011] In the third aspect, the valve joints (80a, 80b) can be stably connected to the second pipes (38b, 39b).

[0012] A fourth aspect is any one of the first to third aspects, wherein the connection portion (V) of the plate stack (50, 60) with the first pipe (38, 39, 38a, 39a, 13b, 12b) has a burring that engages with the first pipe (38, 39, 38a, 39a, 13b, 12b).

[0013] In the fourth aspect, the first pipes (38, 39, 38a, 39a, 13b, 12b) can be stably connected to the connection portions (V) of the plate stack (50, 60).

[0014] A fifth aspect is the fourth aspect, wherein the inner surface of the burring is provided with a clad layer containing a brazing material.

[0015] In the fifth aspect, the first pipes (38, 39, 38a, 39a, 13b, 12b) can be stably connected to the connection portions (V) of the plate stack (50, 60).

[0016] In a sixth aspect, in the second aspect, the end portions (381, 391) of the first pipes (38a, 39a) on the valve joint (80a, 80b) side are provided with flared portions.

[0017] In the sixth aspect, the second pipes (38b, 39b) can be connected to the flared portions of the first pipes (38a, 39a).

[0018] In a seventh aspect, in the sixth aspect, the flared portion is arranged in a direction perpendicular to a surface of the outer surface of the plate stack (50, 60) to which the first pipe (38a, 39a) is connected.

[0019] In the seventh aspect, the second pipes (38b, 39b) can be easily connected to the flared portions of the first pipes (38a, 39a).

[0020] An eighth aspect is the sixth or seventh aspect, wherein the flared portion of the first pipe (38a, 39a) and the second pipe (38b, 39b) are connected by brazing using ring solder.

[0021] In the eighth aspect, the second pipes (38b, 39b) can be connected to the first pipes (38a, 39a) by brazing using ring solder.

[0022] A ninth aspect is any one of the first to eighth aspects, wherein the material of the plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) is the same as the material of the first pipes (38, 39, 38a, 39a, 13b, 12b).

[0023] In the ninth aspect, the first pipes (38, 39, 38a, 39a, 13b, 12b) can be stably connected to the plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) of the plate stack (50, 60).

[0024] A tenth aspect is any one of the first to third aspects, wherein the valve joints (80a, 80b) are made of copper or stainless steel.

[0025] In the tenth embodiment, the valve joints (80a, 80b) can be made of copper or stainless steel.

[0026] In an eleventh aspect, in the tenth aspect, the valve fittings (80a, 80b) are connected to a pipe made of a metal different from that of the valve fittings (80a, 80b), and the pipe is the first pipe (38, 39), or the pipe is a second pipe (38b, 39b) that is different from the first pipe (38a, 39a) and is connected to the plate stack (50, 60) via the first pipe (38a, 39a).

[0027] In an eleventh aspect, the pipes connected to the valve joints (80a, 80b) may be pipes made of a metal different from that of the valve joints (80a, 80b).

[0028] A twelfth aspect is any one of the first to eleventh aspects, wherein the plate stack (50, 60) includes a first plate stack (50) and a second plate stack (60), and the first piping (38, 39, 38a, 39a) includes a piping (38, 38a) connected to the first plate stack (50) and a piping (39, 39a) connected to the second plate stack (60).

[0029] In the twelfth aspect, the heat exchanger can be configured with two heat exchange sections (40A, 40B).

[0030] In a thirteenth aspect, in the twelfth aspect, the pipe (38a) connected to the first plate stack (50) and the pipe (39a) connected to the second plate stack (60) extend in the same direction.

[0031] In the thirteenth aspect, the connectability of the valve joints (80a, 80b) to the first plate assembly (50) and the second plate assembly (60) can be improved.

[0032] A fourteenth aspect relates to a heat exchanger. The heat exchanger includes a heat exchange section (40A, 40B) including fins (41) and heat transfer tubes (42) having a first refrigerant flow path (42c) formed therein, the heat exchange section (40A, 40B) including the fins (41) and the heat transfer tubes (42) fixed to each other by brazing, and a plurality of stacked plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) in which adjacent plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) are fixed to each other by brazing in a stacking direction, and a second refrigerant flow path (40A, 40B) communicating with the first refrigerant flow path (42c) is formed therein. The refrigerant flow path (51, 61) is formed in a plate stack (50, 60), and a first pipe (38, 39, 38a, 39a, 13b, 12b) is formed therein with a third refrigerant flow path (W1) communicating with the second refrigerant flow path (51, 61). The heat exchange section (40A, 40B) and the first pipe (38, 39, 38a, 39a, 13b, 12b) are connected to the plate stack (50, 60) by brazing, and a valve joint (80a, 80b) or an auxiliary pipe (13a, 12a) is directly or indirectly connected to the first pipe (38, 39, 38a, 39a, 13b, 12b).

[0033] In the fourteenth aspect, the first pipes (38, 39, 38a, 39a, 13b, 12b) are connected to the plate stack (50, 60) by brazing, so that the brazing material provided at the connection portion (V) between the plate stack (50, 60) and the first pipes (38, 39, 38a, 39a, 13b, 12b) can be prevented from flowing into the second refrigerant flow path (51, 61).

[0034] In a fifteenth aspect, in the fourteenth aspect, second pipes (38b, 39b) are connected between the first pipes (38a, 39a) and the valve joints (80a, 80b).

[0035] In a sixteenth aspect, in the fifteenth aspect, the second pipes (38b, 39b) and the valve joints (80a, 80b) are made of the same material. [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 is a piping diagram of an air conditioning apparatus according to an embodiment. [Figure 2] FIG. 2 is a front view of the air conditioning indoor unit. [Figure 3] FIG. 3 is a cross-sectional view of the air conditioning indoor unit. [Figure 4] FIG. 4 is a front view showing the internal structure of the air conditioning indoor unit. [Figure 5] FIG. 5 is an enlarged perspective view of a part of the heat exchanger body. [Figure 6] FIG. 6 is a perspective view of the header. [Figure 7] FIG. 7 is an enlarged perspective view of a part of the indoor heat exchanger. [Figure 8] FIG. 8 shows the plate stack as seen from the left side. [Figure 9] FIG. 9 is a cross-sectional view illustrating a refrigerant passage of a plate stack. [Figure 10] FIG. 10 is a partial perspective view of the front plate stack. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 12 is a view of the rear plate stack from the right side. [Figure 13] FIG. 13 is a flow diagram of a method for manufacturing a heat exchanger. [Figure 14] FIG. 14 is a perspective view showing the state of components of the heat exchanger in the brazing process. [Figure 15] FIG. 15 is a flow chart of a first modified example of the method for manufacturing a heat exchanger. [Figure 16] Figure 16(a) is a perspective view showing the state of the components of the heat exchanger in a brazing step, and Figure 16(b) is a perspective view showing the state of the components of the heat exchanger in a first connecting step. [Figure 17] FIG. 17 is a perspective view showing the state of the components of the heat exchanger in the second connecting step. [Figure 18]Figure 18(a) is a perspective view showing the state of the components of the heat exchanger in a brazing process, and Figure 18(b) is a perspective view showing the state of the components of the heat exchanger in a connecting process. [Figure 19] Figure 19(a) is a perspective view showing the state of the components of the heat exchanger in a brazing process, and Figure 19(b) is a perspective view showing the state of the components of the heat exchanger in a connecting process. [Figure 20] Figure 20(a) is a perspective view showing burring, and Figure 20(b) is a cross-sectional view showing burring. DETAILED DESCRIPTION OF THE INVENTION

[0037] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible within the scope of the technical concept of the present disclosure. Since each drawing is intended to conceptually explain the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding. In each embodiment, modified example, and drawing, the same or equivalent parts are designated by the same reference symbols, and detailed descriptions and descriptions of the accompanying effects will not be repeated.

[0038] (1) Overall configuration of the air conditioning unit This embodiment is an air conditioner 10 including a heat exchanger unit. The air conditioner 10 adjusts the temperature of air in an indoor space I, which is a target space.

[0039] As shown in Fig. 1, the air conditioner (10) is an example of a refrigeration cycle device including a refrigerant circuit (11). The refrigerant circuit (11) is filled with a refrigerant. The refrigerant circuit (11) performs a refrigeration cycle by circulating the refrigerant.

[0040] The air conditioner (10) includes an outdoor unit (20), an indoor unit (30), a first connecting pipe (12), and a second connecting pipe (13). The air conditioner (10) is a pair type having one outdoor unit (20) and one indoor unit (30). The first connecting pipe (12) is a gas connecting pipe, and the second connecting pipe (13) is a liquid connecting pipe.

[0041] The outdoor unit (20) is installed outdoors and includes an outdoor casing (20a), and a compressor (21), an outdoor heat exchanger (22), an outdoor expansion valve (23), a four-way selector valve (24), and an outdoor fan (25) housed in the outdoor casing (20a).

[0042] The compressor (21) is a rotary compressor such as a swing piston type, rotary type, or scroll type. The outdoor heat exchanger (22) exchanges heat between the refrigerant and outdoor air. The outdoor heat exchanger (22) is a fin-and-tube type. The outdoor expansion valve (23) reduces the pressure of the refrigerant. The outdoor expansion valve (23) is an electronic expansion valve. The four-way selector valve (24) switches between a first state (a state indicated by a solid line in FIG. 1 ) and a second state (a state indicated by a dashed line in FIG. 1 ). In the first state, the four-way selector valve (24) connects the discharge port of the compressor (21) to the gas end of the outdoor heat exchanger (22) and connects the suction port of the compressor (21) to the first connecting pipe (12). The four-way selector valve (24) in the second state communicates the discharge port of the compressor (21) with the first connecting pipe (12) and also communicates the suction port of the compressor (21) with the gas end of the outdoor heat exchanger (22). The outdoor fan (25) transports the air flowing through the outdoor heat exchanger (22). The outdoor fan (25) is a propeller fan.

[0043] The indoor unit (30) includes a casing (31), and an indoor heat exchanger (40), an indoor fan (32), and an indoor expansion valve (37) housed in the casing (31).

[0044] (2) Air conditioning indoor unit The indoor unit (30) serving as an indoor air conditioner will be described in detail with reference to Figures 2 to 4. The indoor unit (30) of this embodiment is a wall-mounted type installed on a wall of the indoor space (I). In the following description, the terms "upper," "lower," "right," "left," "front," and "rear" correspond to the directions of the arrows shown in Figures 2 and 3, and the left-right direction is based on the case where the indoor casing (31) is viewed from the front.

[0045] (2-1) Casing 2 and 3, the casing (31) is formed in the shape of a horizontally long box and includes a front plate (31a), a rear plate (31b), an upper plate (31c), a lower plate (31d), a first side plate (31e), and a second side plate (31f).

[0046] The front plate (31a) is formed on the front side of the casing (31) and constitutes the front surface of the casing (31). The rear plate (31b) is formed on the rear side of the casing (31) and constitutes the rear surface of the casing (31). The upper plate (31c) is formed on the upper side of the casing (31) and constitutes the upper surface of the casing (31). The lower plate (31d) is formed on the lower side of the casing (31) and constitutes the lower surface of the casing (31). The first side plate (31e) is formed on the right side of the casing (31) and constitutes the right surface of the casing (31). The second side plate (31f) is formed on the left side of the casing (31) and constitutes the left surface of the casing (31).

[0047] An air inlet (33) is formed in the upper plate (31c), and an air outlet (34) is formed in the lower plate (31d). An air passage (P) is formed inside the casing (31) from the air inlet (33) to the air outlet (34). The air inlet (33) extends in the longitudinal direction of the casing (31). The air inlet (33) is an opening for taking air from the indoor space (I) into the air passage (P). An air outlet (34) is formed in the lower plate (31d). The air outlet (34) extends in the longitudinal direction of the casing (31). The air outlet (34) is an opening for blowing air from the air passage (P) into the indoor space (I).

[0048] (2-2) Filter The indoor unit (30) includes a filter (35). The filter (35) is located at the back of the air inlet (33) and upstream of the indoor heat exchanger (40). The filter (35) collects dust in the air sent from the air inlet (33) to the indoor heat exchanger (40). The indoor unit (30) may include a dust removal mechanism that removes the dust collected by the filter (35).

[0049] (2-3) Heat exchanger unit The heat exchanger unit (U) includes one indoor heat exchanger (40) and one indoor expansion valve (37). The indoor heat exchanger (40) includes one heat exchanger body (B) and two plate stacks (50, 60). The heat exchanger body (B) of the indoor heat exchanger (40) is disposed so as to cross the air passage (P). The air passage (P) is divided into an upstream side and a downstream side of the heat exchanger body (B).

[0050] (2-4) Indoor fan The indoor fan (32) is disposed in the air passage (P). The indoor fan (32) is disposed in the air passage (P) downstream of the indoor heat exchanger (40). The indoor fan (32) is a cross-flow fan. The fan rotor of the indoor fan (32) extends in the longitudinal direction of the casing (31).

[0051] (2-5) Flap The indoor unit (30) has a flap (36) that adjusts the direction of air blown out from the air outlet (34). The flap (36) adjusts the air direction in the vertical direction. The indoor unit (30) may have multiple flaps (36). The flap (36) may adjust the air direction in the horizontal direction.

[0052] (3) Heat exchanger unit As described above, the heat exchanger unit (U) includes the indoor heat exchanger (40), the indoor expansion valve (37), the gas relay pipe (12a), and the liquid relay pipe (13a).

[0053] (3-1) Indoor heat exchanger The indoor heat exchanger (40) shown in Figures 3 to 6 includes a heat exchanger body (B) and a plate stack (50, 60) connected to the heat exchanger body (B). The indoor heat exchanger (40) is a microchannel heat exchanger. The indoor heat exchanger (40) exchanges heat between air and a refrigerant.

[0054] The heat exchanger body (B) has a plurality of fins (41) arranged in the longitudinal direction of the casing (31), a plurality of heat transfer tubes (42) extending in the direction of arrangement of the fins (41), and a header (49). A first refrigerant flow path (42c) is formed inside the heat transfer tubes (42). The plate stacks (50, 60) have second refrigerant flow paths (51, 61) therein that communicate with the first refrigerant flow paths (42c) of the heat transfer tubes (42).

[0055] The arrangement direction of the fins (41) corresponds to the longitudinal direction of the casing (31) (left-right direction in FIG. 4). The fins (41) are rectangular plate-shaped having long and short sides. The thickness direction of the fins (41) corresponds to the arrangement direction of the fins (41). The multiple fins (41) are arranged at predetermined intervals in the thickness direction. This interval forms an air passage. Multiple fin grooves (41a) are formed in the fins (41). The multiple fin grooves (41a) are aligned along the longitudinal direction of the fins (41) (up-down direction in FIG. 4). The longitudinal direction of the fins (41) is perpendicular to the longitudinal direction of the casing (31). The fins (41) are made of an aluminum alloy.

[0056] The heat transfer tubes (42) are flat tubes. The heat transfer tubes (42) are made of an aluminum alloy. The heat transfer tubes (42) extend along the longitudinal direction of the casing (31). The heat transfer tubes (42) are inserted into the fin grooves (41a) arranged in the longitudinal direction of the casing (31). The heat transfer tubes (42) extend parallel to one another. One end (42a) of each heat transfer tube (42), i.e., a right end, protrudes to the right of the fins (41). The one end (42a) of each heat transfer tube (42) is connected to the plate stack (50, 60). The other end (42b) of each heat transfer tube (42), i.e., a left end, protrudes to the left of the fins (41).

[0057] The header (49) is provided on the left side of the fin (41). The other ends (42b) of the heat transfer tubes (42) are connected to the header (49). The header (49) is made of, for example, aluminum or an aluminum alloy. The header (49) includes a plurality of insertion holes (49a). The other ends (42b) of the heat transfer tubes (42) are inserted into the insertion holes (49a). The header (49) has a connecting passage for connecting the other ends (42b) of different heat transfer tubes (42) among the plurality of heat transfer tubes (42) to each other. This allows refrigerant to be exchanged between the different heat transfer tubes (42).

[0058] In this embodiment, two rows of heat exchange groups (G) are provided, each row including a plurality of fins (41) arranged in the longitudinal direction of the casing (31) and a plurality of heat transfer tubes (42) arranged in the longitudinal direction of the fins (41) and inserted into the fin grooves (41 a). In this embodiment, the plurality of heat transfer tubes (42) constituting the first row of heat exchange groups (G) communicate with the plurality of heat transfer tubes (42) constituting the second row of heat exchange groups (G) via a header (49). The number of heat exchange groups (G) included in the heat exchanger body (B) is not particularly limited. Alternatively, the heat transfer tubes (42) may be arranged between the fins (41), with one side of the heat transfer tube (42) inserted into the fin grooves (41 a) of one fin (41) and the other side of the heat transfer tube (42) inserted into the fin grooves (41 a) of the other fin (41) (double insertion micro). In addition, although the heat transfer tubes (42) are arranged in a staggered pattern in the embodiment (see FIG. 5), the present invention is not limited to this. For example, the heat transfer tubes (42) may be arranged in an in-line matrix.

[0059] As shown in Fig. 7, the indoor heat exchanger (40) of this embodiment includes a heat exchange section. The heat exchange section has a front heat exchange section (40A) that is a first heat exchange section and a rear heat exchange section (40B) that is a second heat exchange section. The front heat exchange section (40A) is located toward the front of the casing (31), and the rear heat exchange section (40B) is located toward the rear of the casing (31) (see Fig. 4). The front heat exchange section (40A) and the rear heat exchange section (40B) are aligned in a direction perpendicular to both the up-down direction and the axial direction of the heat transfer tube (42), i.e., in the front-rear direction, with the indoor fan (32) (see Fig. 3) sandwiched therebetween.

[0060] As shown in FIG. 3, the front heat exchange section (40A) includes a front main heat exchange section (43), a first auxiliary heat exchange section (44), and a second auxiliary heat exchange section (45).

[0061] The front main heat exchange section (43) is disposed in the front heat exchange section (40A) closer to the indoor fan (32). The front main heat exchange section (43) has a V-shaped outer shape when viewed in the longitudinal direction of the heat transfer tubes (42). The tip of the V faces forward.

[0062] The first auxiliary heat exchange section (44) is provided on the inlet side (front side) of the first front main heat exchange section (43a). The second auxiliary heat exchange section (45) is provided on the inlet side (front side) of the second front main heat exchange section (43b). The rear heat exchange section (40B) has a rear main heat exchange section (46), a third auxiliary heat exchange section (47), and a tube plate. The rear main heat exchange section (46) is disposed in the rear heat exchange section (40B) closer to the indoor fan (32). The third auxiliary heat exchange section (47) is provided on the inlet side (rear side) of the rear main heat exchange section (46). The tube plate of the rear heat exchange section (40B) faces the rear plate stack (60).

[0063] As shown in FIGS. 11 and 12 , one end (42a) of the heat transfer tube (42) is connected to a connecting pipe (53, 63) of the plate stack (50, 60). The connecting pipe (53, 63) is a cylindrical member having an inner surface in an elliptical arc shape that conforms to the outer shape of the one end (42a) of the heat transfer tube (42). The connecting pipe (53, 63) protrudes from the plates (521, 621) of the plate stack (50, 60). The connecting pipe (53, 63) may be a member integral with the plates (521, 621) of the plate stack (50, 60) or may be a member separate from the plates (521, 621). The internal space of the connecting pipe (53, 63) is in communication with the second refrigerant flow path (51, 61) of the plate stack (50, 60). One end (42a) of the heat transfer tube (42) is inserted into the connecting pipe (53, 63) and connected to the connecting pipe (53, 63). As a result, the first refrigerant flow path (42c) of the heat transfer tube (42) communicates with the plate stack (50, 60) of the plate stack (50, 60) via the connecting pipe (53, 63).

[0064] As shown in FIG. 4, the plate stack (50, 60) is disposed to the right of the rightmost fin (41) and parallel to the fin (41). The plate stack (50, 60) is connected to one end (42a) of the heat transfer tube (42). As shown in FIG. 7, the plate stack (50, 60) includes a front plate stack (50) connected to the heat transfer tube (42) of the front heat exchange section (40A) and a rear plate stack (60) connected to the heat transfer tube (42) of the rear heat exchange section (40B). The front plate stack (50) is disposed so as to overlap the front heat exchange section (40A) in the axial direction of the heat transfer tube (42). The rear plate stack (60) is disposed so as to overlap the rear heat exchange section (40B) in the axial direction of the heat transfer tube (42).

[0065] (3-2) Indoor expansion valve, gas relay pipe, liquid relay pipe As shown in FIG. 7 , the indoor expansion valve (37) is an electronic expansion valve with a variable opening. The indoor expansion valve (37) is disposed on the right side of the plate stack (50, 60). The indoor unit (30) includes a first valve joint (80a) and a second valve joint (80b). The first valve joint (80a) and the second valve joint (80b) are each made of, for example, copper or stainless steel. The first valve joint (80a) and the second valve joint (80b) are each connected to the indoor expansion valve (37). The first valve joint (80a) and the second valve joint (80b) are each a tubular member, and a flow path for sending refrigerant is formed therein. The indoor expansion valve (37) is interposed between the first valve joint (80a) and the second valve joint (80b). The refrigerant is sent between the first valve joint (80a) and the second valve joint (80b) via the indoor expansion valve (37). The first valve joint (80a) is connected to the first internal pipe (38). The second valve joint (80b) is connected to the second internal pipe (39). The refrigerant sent from the front plate assembly (50) is sent to the indoor expansion valve (37) through the first internal pipe (38) and the first valve joint (80a). The refrigerant passing through the indoor expansion valve (37) is sent to the rear plate assembly (60) through the second valve joint (80b) and the second internal pipe (39). The internal pipes (38, 39) are tubular members having a bent or curved shape and open at both ends (381, 382, 391, 392). The internal pipes (38, 39) are a first example of the first pipe.

[0066] One end of the gas relay pipe (12a) is connected to the rear plate stack (60). The other end of the gas relay pipe (12a) is connected to the first connecting pipe (12) via a joint. One end of the liquid relay pipe (13a) is connected to the front plate stack (50). The other end of the liquid relay pipe (13a) is connected to the second connecting pipe (13) via a joint.

[0067] (4) Plate stack The plate stack (50, 60) will be described in detail with reference to FIGS.

[0068] (4-1) Front plate stack The front plate stack (50) includes a front main body portion (52) having a second refrigerant flow path (51) therein, a plurality of front connecting pipes (53) connecting the plurality of heat transfer pipes (42) of the front heat exchange portion (40A) to the second refrigerant flow path (51), a front relay portion (54) to which the first internal piping (38) is connected, and a liquid end portion (55) communicating with the second connection piping (13) via the liquid relay pipe (13a).

[0069] As shown in FIGS. 7 and 10 , the front main body portion (52) is a thick plate-like member formed by stacking five front plates. The stacking direction of the front plates is the same as the axial direction of the heat transfer tubes (42). In the front plate stack (50), a first front plate (521), a second front plate (522), a third front plate (523), a fourth front plate (524), and a fifth front plate (525) are stacked in order from the side closest to the front heat exchange section (40A). The second front plate (522), the third front plate (523), and the fourth front plate (524) are intermediate plates sandwiched between the first front plate (521) and the fifth front plate (525). The five front plates are flat plate-like members having the same outer edge shape. Each front plate is made of the same material as the heat transfer tubes (42) and the front connecting tubes (53). In this embodiment, the material of each front plate is, for example, an aluminum alloy. Note that the number of front plates is just an example, and the number of front plates may be four or less, or six or more. Hereinafter, when there is no need to distinguish between the front plates, they will simply be referred to as front plates.

[0070] The plurality of front connecting pipes (53) include a front main connecting pipe (53a) and a front auxiliary connecting pipe (53b). The front main connecting pipe (53a) is connected to the heat transfer pipes (42) of the front main heat exchange section (43).

[0071] 7, the front relay portion (54) is a circular pipe. The front relay portion (54) is provided on the fifth front plate (525). The front relay portion (54) is connected to the end of the front first internal pipe (38) by brazing.

[0072] The liquid end portion (55) is a circular pipe and is provided on the fifth front plate (525). The liquid end portion (55) is connected to the end portion of the liquid relay pipe (13a) by brazing.

[0073] (4-2) Rear plate laminate As shown in FIG. 7, the rear plate stack (60) includes a rear main body portion (62) having a second refrigerant flow path (61) therein, a plurality of rear connecting pipes (63) connecting the plurality of heat transfer tubes (42) of the rear heat exchange portion (40B) to the second refrigerant flow path (61), a rear relay portion (64) to which the second internal piping (39) is connected, and a gas end portion (65) communicating with the first connection piping (12) via the gas relay pipe (12a).

[0074] The rear main body portion (62) has basically the same configuration as the front main body portion (52), except for the shape of the outer edges of the plates as viewed in the axial direction of the heat transfer tubes (42) and the second refrigerant flow paths (61) therein. The rear main body portion (62) is a thick plate-like member formed by stacking five rear plates. The stacking direction of the rear plates is the same as the axial direction of the heat transfer tubes (42). In the rear plate stack (60), a first rear plate (621), a second rear plate (622), a third rear plate (623), a fourth rear plate (624), and a fifth rear plate (625) are stacked in order from the side closest to the rear heat exchange section (40B). The second rear plate (622), the third rear plate (623), and the fourth rear plate (624) are intermediate plates sandwiched between the first rear plate (621) and the fifth rear plate (625). The rear plates are made of the same material as the heat transfer tubes (42) and the rear connecting pipe (63). In this embodiment, the rear plates are made of, for example, an aluminum alloy. Note that the number of rear plates is just an example, and the number of rear plates may be four or less, or six or more. The number of front plates may be different from the number of rear plates. Hereinafter, when it is not necessary to distinguish between the rear plates, they will simply be referred to as rear plates.

[0075] The rear connecting pipe (63) is a circular pipe. The rear connecting pipe (63) is made of an aluminum alloy. As shown in FIG. 12 , the rear connecting pipes (63) are arranged in a manner corresponding to the arrangement of the heat transfer pipes (42) of the rear heat exchange section (40B). In the rear plate stack (60), one end (42a) of the heat transfer pipe (42) is inserted into the rear connecting pipe (63).

[0076] The rear relay portion (64) is a circular pipe. As shown in Fig. 8, the rear relay portion (64) is provided on the fifth rear plate (625). The rear relay portion (64) is connected to an end of the second internal pipe (39) by brazing.

[0077] The gas end portion (65) is a circular pipe and is provided on the fifth rear plate (625). The gas end portion (65) is connected (joined) to an end portion of the gas relay pipe (12a) by brazing.

[0078] (5) Driving behavior The air conditioner (10) performs cooling operation, heating operation, and dehumidifying operation.

[0079] (5-1) Cooling operation As shown in FIG. 1, in cooling operation, the controller of the air conditioner (10) operates the compressor (21), the outdoor fan (25), and the indoor fan (32), sets the four-way switching valve (24) to the first state (the state shown by the solid line in FIG. 1), appropriately adjusts the opening of the outdoor expansion valve (23), and fully opens the indoor expansion valve (37).

[0080] During the cooling operation, the refrigerant circuit (11) performs a refrigeration cycle in which the outdoor heat exchanger (22) functions as a condenser (heat radiator) and the indoor heat exchanger (40) functions as an evaporator.

[0081] The indoor unit (30) draws indoor air from the indoor space (I) into the air passage (P) through the inlet (33). The air in the air passage (P) is cooled by the indoor heat exchanger (40). The cooled air is supplied to the indoor space (I) through the outlet (34).

[0082] (5-2) Heating operation In the heating operation, the controller of the air conditioner (10) operates the compressor (21), the outdoor fan (25), and the indoor fan (32), sets the four-way switching valve (24) to the second state (the state indicated by the dashed line in FIG. 1 ), adjusts the opening of the outdoor expansion valve (23) to a predetermined opening, and fully opens the indoor expansion valve (37).

[0083] During the heating operation, the refrigerant circuit (11) performs a refrigeration cycle in which the indoor heat exchanger (40) functions as a condenser (heat radiator) and the outdoor heat exchanger (22) functions as an evaporator.

[0084] The indoor unit (30) draws indoor air from the indoor space (I) into the air passage (P) through the inlet (33). The air in the air passage (P) is heated by the indoor heat exchanger (40). The heated air is supplied to the indoor space (I) through the outlet (34).

[0085] (5-3) Dehumidification operation In the dehumidifying operation, the controller of the air conditioner (10) operates the compressor (21), the outdoor fan (25), and the indoor fan (32), sets the four-way switching valve (24) to the first state (the state shown by the solid line in FIG. 1), and appropriately adjusts the openings of the outdoor expansion valve (23) and the indoor expansion valve (37).

[0086] During the dehumidifying operation, the refrigerant circuit (11) performs a refrigeration cycle in which the outdoor heat exchanger (22) and the front heat exchange section (40A) of the indoor heat exchanger (40) function as condensers (radiators), and the rear heat exchange section (40B) of the indoor heat exchanger (40) functions as an evaporator.

[0087] The indoor unit (30) draws room air from the indoor space (I) into the air passage (P) through the inlet (33). The rear heat exchanger (40B) cools the air in the air passage (P) to a temperature below the dew point. The front heat exchanger (40A) heats the air in the air passage (P). The air passing through both the rear heat exchanger and the front heat exchanger mixes in the air passage (P) to produce low-humidity air. The dehumidified air is supplied to the indoor space (I) through the outlet (34).

[0088] (6) Heat exchanger manufacturing method 13 and 14, a brazing process is performed in step S1. In the brazing process, with the front heat exchange section (40A) and the first internal piping (38) assembled to the front plate stack (50), the front heat exchange section (40A), the front plate stack (50), and the first internal piping (38) are simultaneously brazed in a furnace. As a result, the fins (41) and the heat transfer tubes (42) of the front heat exchange section (40A) are fixed to each other by the brazing material, and among the plurality of front plates (521, 522, 523, 524, 525) included in the front plate stack (50), adjacent front plates in the stacking direction of the front plates (521, 522, 523, 524, 525) are fixed to each other by the brazing material, and further, the front heat exchange section (40A) and the first internal piping (38) are connected to the front plate stack (50). The brazing material is, for example, an aluminum alloy brazing material. The connection of the front heat exchange section (40A) and the first internal piping (38) to the front plate stack (50) means that one end (42a) of the heat transfer tube (42) and the connecting pipe (53) of the front plate stack (50) are fixed to each other with brazing material (see FIG. 11), and further, one end (381) of the first internal piping (38) and the front relay section (54) of the front plate stack (50) are fixed to each other with brazing material (see FIG. 14).

[0089] In the brazing step, with the rear heat exchange section (40B) and the second internal piping (39) assembled to the rear plate stack (60), the rear heat exchange section (40B), the rear plate stack (60), and the second internal piping (39) are simultaneously brazed by furnace brazing. As a result, the fins (41) and the heat transfer tubes (42) of the rear heat exchange section (40B) are fixed to each other with the brazing material, rear plates (621, 622, 623, 624, 625) adjacent to each other in the stacking direction of the rear plates (621, 622, 623, 624, 625) of the rear plate stack (60) are fixed to each other with the brazing material, and further the rear heat exchange section (40B) and the second internal piping (39) are connected to the rear plate stack (60). The connection of the rear heat exchange section (40B) and the second internal piping (39) to the rear plate stack (60) means that one end (42a) of the heat transfer tube (42) and the connecting pipe (63) of the rear plate stack (60) are fixed to each other with brazing material, and further, one end (391) of the second internal piping (39) and the rear relay section (64) of the rear plate stack (60) are fixed to each other with brazing material.

[0090] As shown in FIGS. 7 and 13, in step S2, after the brazing step (step S1), the valve joints (80a, 80b) are connected (fixed) to the internal pipes (38, 39). Specifically, the other end (382) of the first internal pipe (38) is connected to the first valve joint (80a) by brazing, and further, the other end (392) of the second internal pipe (39) is connected to the second valve joint (80b) by brazing. The valve joints (80a, 80b) are connected to the internal pipes (38, 39) by, for example, burner brazing. The internal pipes (38, 39) and the valve joints (80a, 80b) are brazed outside the furnace.

[0091] After the brazing step, the liquid relay pipe (13a) is connected to the liquid end (55) by brazing, and the gas relay pipe (12a) is connected to the gas end (65) by brazing. In this embodiment, the relay pipes (13a, 12a) are connected to the end (55, 65) by burner brazing outside the furnace. The reason why the connection between the internal pipes (38, 39) and the valve joints (80a, 80b) is performed outside the furnace is that, due to the heat resistance of the indoor expansion valve (37), it is not preferable to connect the internal pipes (38, 39) and the valve joints (80a, 80b) by furnace brazing.

[0092] (7) Effects As described above, in the brazing step, the heat exchange units (40A, 40B), the plate stack (50, 60), and the internal pipes (38, 39) are brazed together simultaneously. This fixes the fins (41) and the heat transfer tubes (42) to each other, fixes the plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) adjacent to each other in the stacking direction, and connects the heat exchange units (40A, 40B) and the internal pipes (38, 39) to the plate stack (50, 60). After the brazing step, in the connecting step, the valve joints (80a, 80b) are directly connected to the internal pipes (38, 39). According to this, in the brazing process, when the plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) are brazed together, the first pipes (38, 39, 38a, 39a, 13b, 12b) are simultaneously brazed to the plate stack (50, 60) using the brazing material provided at the connection portion (V) (see Figure 19(b)) between the plate stack (50, 60) and the internal pipes (38, 39). As a result, when the plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) are brazed together, the brazing material applied to the connection portion (V) (the brazing material applied to connect the internal pipes (38, 39) to the plate stack (50, 60)) can be prevented from melting and flowing into the second refrigerant flow path (51, 61).

[0093] (8) First Modification of the Method for Manufacturing a Heat Exchanger As shown in FIG. 16(b), the first modified example differs from the embodiment in that the plate stack (50, 60) is connected to the valve joints (80a, 80b) via the internal pipes (38a, 39a) and (38b, 39b). The internal pipes (38a, 39a) are tubular members extending in a straight line and formed in a line segment. Openings are formed at both ends (38a1, 38a2, 39a1, 39a2) of the internal pipes (38a, 39a). The internal pipes (38a, 39a) may be bent or curved. The internal pipes (38a, 39a) are a second example of the first pipe. The internal pipes (38b, 39b) are tubular members having a bent or curved shape and openings at both ends (38b1, 38b2, 39b1, 39b2). The internal pipes (38b, 39b) are an example of the second pipe.

[0094] 15 and 16(a), a brazing process is performed in step S11. In the brazing process, with the front heat exchange section (40A) and the third internal piping (38a) assembled to the front plate stack (50), the front heat exchange section (40A), the front plate stack (50), and the third internal piping (38a) are simultaneously brazed together by furnace brazing. As a result, the fins (41) and the heat transfer tubes (42) of the front heat exchange section (40A) are fixed to each other with the brazing material, adjacent front plates of the front plates (521, 522, 523, 524, 525) in the stacking direction are fixed to each other with the brazing material, and further the front heat exchange section (40A) and the third internal piping (38a) are connected to the front plate stack (50). The connection of the third internal piping (38a) to the front plate stack (50) means that one end (38a1) of the third internal piping (38a) and the front relay portion (54) of the front plate stack (50) are fixed to each other with solder.

[0095] In the brazing step, with the rear heat exchange section (40B) and the fourth internal piping (39a) assembled to the rear plate stack (60), the rear heat exchange section (40B), the rear plate stack (60), and the fourth internal piping (39a) are simultaneously brazed together by furnace brazing. As a result, the fins (41) and the heat transfer tubes (42) of the rear heat exchange section (40B) are fixed to each other with the brazing material, adjacent rear plates in the stacking direction among the rear plates (621, 622, 623, 624, 625) are fixed to each other with the brazing material, and further the rear heat exchange section (40B) and the fourth internal piping (39a) are connected to the rear plate stack (60). The connection of the fourth internal pipe (39a) to the rear plate stack (60) means that one end (39a1) of the fourth internal pipe (39a) and the rear relay portion (64) of the rear plate stack (60) are fixed to each other with brazing material.

[0096] As shown in FIGS. 15 and 16(b), in step S12, after the brazing step (step S11), the internal pipes (38b, 39b) are connected (fixed) to the internal pipes (38a, 39a). Specifically, the other end (38a2) of the third internal pipe (38a) is connected to one end (38b1) of the fifth internal pipe (38b) by brazing, and further the other end (39a2) of the fourth internal pipe (39a) is connected to one end (39b1) of the sixth internal pipe (39b) by brazing. The internal pipes (38b, 39b) are connected to the internal pipes (38a, 39a) by, for example, burner brazing. The internal pipes (38a, 39a) and the internal pipes (38b, 39b) are brazed outside the furnace.

[0097] 15 and 17, in step S13, the valve joints (80a, 80b) are connected to the internal pipes (38b, 39b). Specifically, the other end (38b2) of the fifth internal pipe (38b) is connected to the first valve joint (80a) by brazing, and the other end (39b2) of the sixth internal pipe (39b) is connected to the second valve joint (80b) by brazing. The valve joints (80a, 80b) are connected to the internal pipes (38b, 39b) by, for example, burner brazing. The internal pipes (38b, 39b) and the valve joints (80a, 80b) are brazed outside the furnace.

[0098] After the brazing step, the liquid relay pipe (13a) is connected to the liquid end (55) by brazing, and the gas relay pipe (12a) is connected to the gas end (65) by brazing.

[0099] As described above, in the first modified example, after the brazing step, the internal pipes (38b, 39b) are connected to the internal pipes (38a, 39a), and the valve joints (80a, 80b) are further connected to the internal pipes (38b, 39b). That is, in the first modified example, after the brazing step, the internal pipes (38b, 39b) are connected between the internal pipes (38a, 39a) and the valve joints (80a, 80b), thereby indirectly connecting the valve joints (80a, 80b) to the internal pipes (38a, 39a) via the internal pipes (38b, 39b). By connecting the internal pipes (38b, 39b) between the internal pipes (38a, 39a) and the valve joints (80a, 80b), the first structure in which the heat exchange units (40A, 40B) and the internal pipes (38a, 39a) are assembled to the plate stack (50, 60) can be made compact. Therefore, in the brazing step, the first structure can be easily placed in a furnace, and the first structure can be easily brazed in the furnace.

[0100] (9) Second Modification of the Method for Manufacturing a Heat Exchanger As shown in FIG. 18(a), the second modification differs from the embodiment in that the plate stack (50, 60) is connected to the relay pipes (13a, 12a) via the connection pipes (13b, 12b). The connection pipes (13b, 12b) are tubular members extending in a straight line and formed in the shape of a line segment. Openings are formed at both ends (13b1, 13b2, 12b1, 12b2) of the connection pipes (13b, 12b). The connection pipes (13b, 12b) may be bent or curved. The connection pipes (13b, 12b) are a third example of the first pipe. The relay pipes (13a, 12a) are an example of the auxiliary pipe.

[0101] 18(b), in the second modified example, a brazing process is first performed. In the brazing process of the second modified example, with the front heat exchange section (40A) and the first connection pipe (13b) assembled to the front plate stack (50), the front heat exchange section (40A), the front plate stack (50), and the first connection pipe (13b) are simultaneously brazed by furnace brazing. As a result, the fins (41) and the heat transfer tubes (42) of the front heat exchange section (40A) are fixed to each other with the brazing material, adjacent front plates of the front plates (521, 522, 523, 524, 525) in the stacking direction are fixed to each other with the brazing material, and further the front heat exchange section (40A) and the first connection pipe (13b) are connected to the front plate stack (50). The connection of the first connecting pipe (13b) to the front plate stack (50) means that one end (13b1) of the first connecting pipe (13b) and the liquid end (55) of the front plate stack (50) are fixed to each other with brazing material.

[0102] In the brazing step of the second modified example, the rear heat exchange section (40B) and the second connection pipe (12b) are assembled to the rear plate stack (60), and the rear heat exchange section (40B), the rear plate stack (60), and the second connection pipe (12b) are simultaneously brazed by furnace brazing. As a result, the fins (41) and the heat transfer tubes (42) of the rear heat exchange section (40B) are fixed to each other with the brazing material, adjacent rear plates in the stacking direction among the rear plates (621, 622, 623, 624, 625) are fixed to each other with the brazing material, and further the rear heat exchange section (40B) and the second connection pipe (12b) are connected to the rear plate stack (60). The connection of the second connection pipe (12b) to the rear plate stack (60) means that one end (12b1) of the second connection pipe (12b) and the gas end (65) of the rear plate stack (60) are fixed to each other with brazing material.

[0103] Next, as shown in FIG. 18(b), after the brazing step, a connecting step is performed. In the connecting step of the second modified example, the relay pipes (13a, 12a) are connected (fixed) to the connection pipes (13b, 12b). Specifically, the other end (13b2) of the first connection pipe (13b) is connected to the liquid relay pipe (13a) by brazing, and further the other end (12b2) of the second connection pipe (12b) is connected to the gas relay pipe (12a) by brazing. The relay pipes (13a, 12a) are directly connected to the connection pipes (13b, 12b), for example, by burner brazing. The brazing of the connection pipes (13b, 12b) to the relay pipes (13a, 12a) is performed outside the furnace. By connecting the relay pipes (13a, 12a) to the plate stack (50, 60) via the connecting pipes (13b, 12b), the second structure in which the heat exchange units (40A, 40B) and the connecting pipes (13b, 12b) are assembled to the plate stack (50, 60) can be made compact. Therefore, in the brazing step, the second structure can be easily placed in a furnace, and the second structure can be easily brazed in the furnace.

[0104] In addition, in the connecting step of the second modified example, outside the furnace, the first internal pipe (38) is connected to the front plate stack (50) by burner brazing, the first valve joint (80a) is connected to the first internal pipe (38), and further the second internal pipe (39) and the second valve joint (80b) are connected to the rear plate stack (60).

[0105] In the brazing step of the second modified example, the front heat exchange section (40A), the front plate assembly (50), the first internal pipe (38), and the first connecting pipe (13b) may be simultaneously brazed by furnace brazing, and the rear heat exchange section (40B), the rear plate assembly (60), the second internal pipe (39), and the second connecting pipe (12b) may be simultaneously brazed by furnace brazing. After the brazing step, the valve joints (80a, 80b) are connected to the internal pipes (38, 39) (burner brazing), and the relay pipes (13a, 12a) are connected to the connecting pipes (13b, 12b) (burner brazing).

[0106] Furthermore, in the second modified example, as in the above-described first modified example, a configuration may be adopted in which the plate stacks (50, 60) are connected to the valve joints (80a, 80b) via the internal pipes (38a, 39a) and the internal pipes (38b, 39b) (see FIG. 17 ). In this case, in the brazing step of the second modified example, the front heat exchange section (40A), the front plate stack (50), the third internal pipe (38a), and the first connecting pipe (13b) may be simultaneously brazed by furnace brazing, and the rear heat exchange section (40B), the rear plate stack (60), the fourth internal pipe (39a), and the second connecting pipe (12b) may be simultaneously brazed by furnace brazing. That is, as shown in FIG. 19( a), in the brazing process, the heat exchange sections (40A, 40B), the plate stack (50, 60), the internal pipes (38a, 39a), and the connecting pipes (13b, 12b) are brazed together (furnace brazing) at the same time, and after the brazing process, as shown in FIG. 19( b), the internal pipes (38b, 39b) are connected to the internal pipes (38a, 39a) (burner brazing), the valve couplings (80a, 80b) are connected to the internal pipes (38b, 39b) (burner brazing), and further the relay pipes (13a, 12a) are connected to the connecting pipes (13b, 12b) (burner brazing).

[0107] (10) Other embodiments As shown in FIGS. 20(a) and 20(b), the connection portion (V) of the plate stack (50, 60) with the first pipe (W) may have a burring that engages with the first pipe (W). The first pipe (W) is at least one of the internal pipes (38, 39, 38a, 39a) and the connecting pipes (13b, 12b). A third refrigerant flow path (W1) that communicates with the second refrigerant flow path (51, 61) is formed inside the first pipe (W). The third refrigerant flow path (W1) formed inside the pipe (38, 38a, 13b) of the first pipe (W) communicates with the second refrigerant flow path (51), and the third refrigerant flow path (W1) formed inside the pipe (39, 39a, 12b) communicates with the second refrigerant flow path (61). The connection portion (V) is the portion of the plate stack (50, 60) to which the first pipe (W) is connected. In the present embodiment, the connection portion (V) is the front relay portion (54), the liquid end portion (55), the rear relay portion (64), and / or the gas end portion (65). This allows the first pipe (W) to be inserted into the burring of the connection portion (V) to engage with it and connect the first pipe (W) to the plate stack (50, 60) by brazing, thereby enabling the first pipe (W) to be stably connected to the connection portion (V) of the plate stack (50, 60).

[0108] The inner surface of the burring of the connection portion (V) may be provided with a clad layer containing a brazing material. This allows the first pipe (W) to be brazed while inserted (engaged) into the burring of the connection portion (V) when the plate stack (50, 60) and the first pipe (W) are brazed in a furnace. This prevents the brazing material on the inner surface of the burring from melting and flowing into the second refrigerant flow path (51, 61) during the furnace brazing, thereby preventing clogging of the second refrigerant flow path (51, 61). As a result, the first pipe (W) can be stably connected to the connection portion (V) of the plate stack (50, 60).

[0109] 17, the internal pipes (38b, 39b) and the valve joints (80a, 80b) may be made of the same material, such as stainless steel, which allows the valve joints (80a, 80b) to be stably connected to the internal pipes (38b, 39b).

[0110] As shown in FIGS. 16(b) and 17, the end portions (381, 391) of the valve joints (80a, 80b) of the internal pipes (38a, 39a) may have a flared portion. The flared portion may be disposed in a direction perpendicular to the outer surface of the plate stack (50, 60) to which the internal pipes (38a, 39a) are connected. In this embodiment, the direction perpendicular to the outer surface of the plate stack (50, 60) to which the internal pipes (38a, 39a) are connected is the stacking direction of the plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) constituting the plate stack (50, 60). In this embodiment, the flared portion has a shape such that the inner diameter gradually increases along the stacking direction as it moves away from the plate stack (50, 60). With this, when connecting the internal pipes (38b, 39b) to the flared portions of the internal pipes (38a, 39a), the one ends (38b1, 39b1) of the internal pipes (38b, 39b) can be easily inserted into the flared portions along the stacking direction, thereby making it possible to easily connect the internal pipes (38b, 39b) to the flared portions of the internal pipes (38a, 39a). Furthermore, the flared portions of the internal pipes (38a, 39a) and the one ends (38b1, 39b1) of the internal pipes (38b, 39b) may be connected by brazing using ring solder. This allows the internal pipes (38b, 39b) to be connected to the internal pipes (38a, 39a) by brazing using ring solder.

[0111] 7, 17, and 18(b), the plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) and the pipes (38, 39, 38a, 39a, 13b, 12b) may be made of the same material (e.g., aluminum or aluminum alloy), which allows the pipes (38, 39, 38a, 39a, 13b, 12b) to be stably connected to the plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625).

[0112] 7, 17, and 18(b), the valve joints (80a, 80b) may be connected to internal pipes (38, 39, 38b, 39b) made of a metal different from that of the valve joints (80a, 80b). This allows the internal pipes (38, 39, 38b, 39b) connected to the valve joints (80a, 80b) to be made of a metal different from that of the valve joints (80a, 80b).

[0113] As shown in FIG. 17 , the third internal pipe (38a) connected to the front plate assembly (50) and the fourth internal pipe (39a) connected to the rear plate assembly (60) may extend in the same direction. In this embodiment, the third internal pipe (38a) and the fourth internal pipe (39a) extend in the stacking direction. This allows the direction in which the fifth internal pipe (38b) is connected to the third internal pipe (38a) and the direction in which the sixth internal pipe (39b) is connected to the fourth internal pipe (39a) to be the same direction (the stacking direction). This facilitates the connection of the valve joints (80a, 80b) to the plate assembly (50, 60) via the internal pipes (38a, 38b, 39a, 39b). As a result, the connectivity of the valve joints (80a, 80b) to the plate assembly (50, 60) can be improved.

[0114] The indoor heat exchanger (40) may be of a fin-and-tube type, or may be of a corrugated type in which corrugated fins are arranged between adjacent heat transfer tubes.

[0115] In this embodiment, the indoor heat exchanger (40) includes two plate stacks (50, 60) and two heat exchange sections (40A, 40B), but the number of plate stacks and the number of heat exchange sections included in the indoor heat exchanger (40) are not particularly limited.

[0116] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and details are possible without departing from the spirit and scope of the claims. Furthermore, the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate as long as the functionality of the subject matter of the present disclosure is not impaired.

[0117] The terms "first," "second," "third," etc. mentioned above are used to distinguish the terms to which these terms are attached, and do not limit the number or order of the terms. [Industrial Applicability]

[0118] As described above, the present disclosure is useful for heat exchangers and methods for manufacturing heat exchangers. [Explanation of symbols]

[0119] 12a Gas relay pipe 12b Second connecting pipe 13a Liquid relay pipe 13b First connecting pipe 38 First internal piping 38a Third internal piping 39 Second internal piping 39a 4th internal piping 40 Indoor heat exchanger 40A Front heat exchanger 40B Rear heat exchange section 41 Finn 42 Heat transfer tube 42c First refrigerant flow path 50 Front plate stack 51 second refrigerant flow path 60 Rear plate stack 61 second refrigerant flow path 80a 1st valve fitting 80b 2nd valve fitting 521 First front plate 522 Second front plate 523 Third front plate 524 4th front plate 525 5th front plate 621 First rear plate 622 Second rear plate 623 Third rear plate 624 4th rear plate 625 5th rear plate W1 Third refrigerant flow path

Claims

1. a heat exchange section (40A, 40B) including a fin (41) and a heat transfer tube (42) having a first refrigerant flow path (42c) formed therein; a plate stack (50, 60) including a plurality of stacked plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) and having a second refrigerant flow path (51, 61) formed therein and communicating with the first refrigerant flow path (42c); and a first piping (50, 60) having a third refrigerant flow path (W1) formed therein and communicating with the second refrigerant flow path (51, 61). a brazing step of simultaneously brazing the plates (38, 39, 38a, 39a, 13b, 12b) to fix the fins (41) and the heat transfer tubes (42) to each other and fix the plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) adjacent to each other in the stacking direction, and further connecting the heat exchange section (40A, 40B) and the first pipes (38, 39, 38a, 39a, 13b, 12b) to the plate stack (50, 60); a step of directly or indirectly connecting a valve joint (80a, 80b) or an auxiliary pipe (13a, 12a) to the first pipe (38, 39, 38a, 39a, 13b, 12b) after the brazing step; A method for manufacturing a heat exchanger, comprising:

2. 2. The method for manufacturing a heat exchanger according to claim 1, further comprising, after the brazing step, connecting a second pipe (38b, 39b) between the first pipe (38a, 39a) and the valve joint (80a, 80b).

3. The method for manufacturing a heat exchanger according to claim 2, wherein the second pipes (38b, 39b) and the valve joints (80a, 80b) are made of the same material.

4. 4. The method for manufacturing a heat exchanger according to claim 1, wherein a connection portion (V) of the plate stack (50, 60) with the first pipe (38, 39, 38a, 39a, 13b, 12b) has a burring that engages with the first pipe (38, 39, 38a, 39a, 13b, 12b).

5. The method for manufacturing a heat exchanger according to claim 4 , wherein the inner surface of the burring is provided with a clad layer containing a brazing material.

6. The method for manufacturing a heat exchanger according to claim 2, wherein an end portion (381, 391) of the first pipe (38a, 39a) on the valve joint (80a, 80b) side includes a flared portion.

7. 7. The method for manufacturing a heat exchanger according to claim 6, wherein the flared portion is arranged in a direction perpendicular to a surface of an outer surface of the plate stack (50, 60) to which the first pipe (38a, 39a) is connected.

8. 8. The method for manufacturing a heat exchanger according to claim 6, wherein the flared portion of the first pipe (38a, 39a) and the second pipe (38b, 39b) are connected to each other by brazing using ring solder.

9. The method for manufacturing a heat exchanger according to any one of claims 1 to 3, wherein the plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) and the first pipes (38, 39, 38a, 39a, 13b, 12b) are made of the same material.

10. The method for manufacturing a heat exchanger according to any one of claims 1 to 3, wherein the valve joints (80a, 80b) are made of copper or stainless steel.

11. a pipe made of a metal different from that of the valve joints (80a, 80b) is connected to the valve joints (80a, 80b); the pipe is the first pipe (38, 39), Or, 11. The method for manufacturing a heat exchanger according to claim 10, wherein the pipe is a second pipe (38b, 39b) that is different from the first pipe (38a, 39a) and is connected to the plate stack (50, 60) via the first pipe (38a, 39a).

12. The plate stack (50, 60) includes a first plate stack (50) and a second plate stack (60), 4. The method for manufacturing a heat exchanger according to claim 1, wherein the first piping (38, 39, 38a, 39a) includes a piping (38, 38a) connected to the first plate stack (50) and a piping (39, 39a) connected to the second plate stack (60).

13. 13. The method for manufacturing a heat exchanger according to claim 12, wherein a pipe (38a) connected to the first plate stack (50) and a pipe (39a) connected to the second plate stack (60) extend in the same direction.

14. a heat exchange section (40A, 40B) including fins (41) and heat transfer tubes (42) having a first refrigerant flow path (42c) formed therein, the fins (41) and the heat transfer tubes (42) being fixed to each other by brazing; a plate stack (50, 60) including a plurality of stacked plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625), in which adjacent plates (521, 522, 523, 524, 525, 621, 622, 623, 624, 625) in the stacking direction are fixed to each other by brazing, and a second refrigerant flow path (51, 61) communicating with the first refrigerant flow path (42c) is formed therein; a first pipe (38, 39, 38a, 39a, 13b, 12b) in which a third refrigerant flow path (W1) communicating with the second refrigerant flow path (51, 61) is formed; Equipped with the heat exchange section (40A, 40B) and the first pipe (38, 39, 38a, 39a, 13b, 12b) are connected to the plate stack (50, 60) by brazing; a valve joint (80a, 80b) or an auxiliary pipe (13a, 12a) is directly or indirectly connected to the first pipe (38, 39, 38a, 39a, 13b, 12b).

15. 15. The heat exchanger according to claim 14, wherein a second pipe (38b, 39b) is connected between the first pipe (38a, 39a) and the valve joint (80a, 80b).

16. 16. The heat exchanger according to claim 15, wherein the second pipes (38b, 39b) and the valve joints (80a, 80b) are made of the same material.

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